Senators on Tuesday gamely struggled to see if there was a way to set aside longstanding partisan differences over a new authorization for use of military force amid expanding military campaigns in Syria and Iraq, and under a new president who has delegated significant tactical authority to his commanders.

The Trump administration is waging its anti-ISIS campaign under the authority of the 2001 AUMF, which Congress passed shortly after the September 11 attacks. Sixteen years later, experts on both sides of the aisle increasingly agree the authorization (PL 107-40) has been stretched beyond almost all legal recognition to justify the occasional air strike on Bashar al-Assad’s forces in Syria and even far-flung groups like Al-Shabab in East Africa.

Rather than highlighting their policy differences, as was the case during the last Congress, Republicans and Democrats at a Foreign Relations Committee hearing Tuesday thanked one another for their attention to the issue and signaled they were ready to make certain compromises to get a final product.

Still, it was not clear there was enough agreement to satisfy Chairman Bob Corker, who reiterated his position that he would not push forward a new authorization if it did not have broad bipartisan backing.

“The failure to bridge differences and to pass a new AUMF could create a false impression of disunity during a time of war,” the Tennessee Republican cautioned.

The main focus of consideration has been on a new AUMF proposal from Sens. Jeff Flake, R-Ariz., and Tim Kaine, D-Va., who co-sponsored an unsuccessful authorization effort in the last Congress.

The new measure (S J Res 43) specifically authorizes military action against al-Qaida, the Taliban and the Islamic State. It also establishes a congressional oversight process for whether other groups or entities can be treated as “associated forces” under the new authorization and if the military campaign expands beyond certain countries. The measure would replace the 2001 AUMF and expire in five years, absent congressional reauthorization.

“We’ve struck a pretty decent balance,” Flake said. “I hope that we can move forward on that basis.”

Sen. Chris Coons, D-Del., threw his support behind the effort, while Sen. Todd Young, R-Ind., said he wants the measure amended to include components from his own resolution (S J Res 31) dealing with the legal authority to detain and imprison ISIS members.

“I am prepared to make principled compromises . . . so that we can formulate an AUMF that can pass this committee,” Young said.

Testifying before the committee, John Bellinger, who served as State Department legal adviser during President George W. Bush’s second term, said “there really is potential legal infirmity” with the 2001 authorization when it comes to detaining ISIS fighters, necessitating a new AUMF.